In manufacturing a semiconductor, liquid crystal device or the like, a plasma processing which employs a plasma has been widely used. In such plasma processing, for components like an electrode exposed to a plasma atmosphere in a chamber, it has been proposed to employ a thermally sprayed film formed on the surface of a basic material of an insulting ceramic with a high corrosion resistance such as alumina (Al2O3), yttrium oxide (Y2O3) or the like, so that they can be resistant to the plasma. (see, e.g., page 3, FIG. 2 of Japanese Patent Laid-open Publication No. H9-339895).
When such thermally sprayed films of alumina, yttrium oxide or the like are formed on a basic nonmetal material like ceramic or quartz, if the thermal spraying is carried out by only performing a beads blast, chemical blast or the like on the surface thereof as when a metal basic material is used, because a dielectric-material component has a low tolerance to a hardening shrinkage of the thermally sprayed film, the anchoring effect of the thermally sprayed film deteriorates. As a result, the thermally sprayed film is readily stripped off. In order to eliminate this problem, there has been proposed a method for thermally spraying a soft-metal thin film. such as aluminum (Al), nickel (Ni) or the like as an intermediate layer between the basic material and the thermally sprayed film to enhance the anchor therebetween (see, e.g., Japanese Patent Laid-open Publication No. H9-69554).
As for the field of plasma processing, a parallel plate type plasma processing apparatus to form a high frequency electric field between a pair of electrodes disposed vertically facing each other has been widely used. In order to generate a high-density plasma by using such apparatus, the applied frequency needs to be increased. However, when the applied frequency is increased as such, not only does the electric field distribution on the electrode surface becomes nonuniform, but also the plasma density becomes nonuniform as well. Therefore, there has been suggested a method for uniformizing the plasma density by providing a dielectric member such as a ceramic or the like at, e.g., the central portion of an exposed surface of an upper electrode so that the electric field distribution is uniformized (see, e.g., Japanese Patent Laid-open Publication No. 2000-323456).
When the thermally sprayed film is formed on a basic material of the electrode having a dielectric member on the surface thereof, if an intermediate layer (bond-coat layer) is formed as described above, the bond-coat layer itself, which is metal, becomes a conductive layer for a high frequency power. Therefore, the dielectric member, which is intended to obstruct the penetration of a high frequency power, is not able to function as expected.